Submission #366461

#	Time	Username	Problem	Language	Result	Execution time	Memory
366461		Vimmer	Papričice (COCI20_papricice)	C++14	50 / 110	669 ms	47596 KiB

papricice

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

//#pragma GCC optimize("-O3")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("-Ofast")

#define N 200500
#define NN 205000
#define PB push_back
#define endl '\n'
#define pri(x) cout << x << endl
#define _ << " " <<
#define all(x) x.begin(), x.end()
#define sz(x) int(x.size())
#define M ll(1e9 + 7)
#define F first
#define S second

using namespace std;
//using namespace __gnu_pbds;

typedef long long ll;
typedef long double ld;
typedef short int si;
typedef unsigned long long ull;

//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;

vector <int> g[N];

int ans = 1e9, siz[N], n;

set <int> se[N];
set <pair <int, int> > st;

void rec(int v, int p)
{
    siz[v] = 1;

    for (auto it : g[v])
    {
        if (it == p) continue;

        rec(it, v);

        siz[v] += siz[it];
    }
}
void dfs(int v, int p)
{
    int val = (n + 3 * siz[v] + 1) / 2;

     if (sz(st))
        {
            int kol = 100;

            auto itr = st.lower_bound({val, -1});

            if (itr == st.end()) itr--;

            while (kol && sz(st))
            {
                int vt = (*itr).F;

                int a1 = n - siz[v] - vt, a2 = siz[v], a3 = vt;

                int val = max(a1, max(a2, a3)) - min(a1, min(a2, a3));

                ans = min(ans, val);

                kol--;

                if (itr == st.begin())
                    break;

                itr--;
            }
        }

    for (auto it : g[v])
    {
        if (it == p) continue;

        dfs(it, v);

        if (sz(se[it]) > sz(se[v]))
            swap(se[it], se[v]);

        for (auto itr : se[it])
          se[v].insert(itr);
    }

    int kol = 100;

    if (sz(se[v]))
    {
        auto it = se[v].lower_bound(val);

        if (it == se[v].end()) it--;

        while (kol && sz(se[v]))
        {
            int vt = (*it);

            int a1 = n - siz[v], a2 = siz[v] - vt, a3 = vt;

            ans = min(ans, max(a1, max(a2, a3)) - min(a1, min(a2, a3)));

            kol--;

            if (it == se[v].begin())
                break;

            it--;
        }
    }

    se[v].insert(siz[v]);

    st.insert({siz[v], v});
}

int main()
{
    ios_base::sync_with_stdio(0); istream::sync_with_stdio(0); cin.tie(0); cout.tie(0);

//    freopen("1.in", "r", stdin);

    cin >> n;

    for (int i = 1; i < n; i++)
    {
        int x, y;

        cin >> x >> y;

        g[x].PB(y);

        g[y].PB(x);
    }

    rec(1, -1);

    dfs(1, -1);

    pri(ans);
}

• Subtask 1: 15 / 15
• Subtask 2: 35 / 35
• Subtask 3: 0 / 60